Vehicle information systems have been developed that provide various types of information to operators of those vehicles. In particular, navigation systems have been developed. One type of navigation system, a self-contained navigation system, uses an on-board map, typically stored on a removable medium such as a compact optical disk (e.g., CD-ROM). The navigation system uses the on-board map to plan a route from a starting point to a destination, which is specified by the operator of the vehicle. Updating an autonomous system's map, for example to add or correct information, typically involves replacing the removable medium.
The data within such navigation systems are provided to the vehicle operator in a number of different approaches. In one approach, the operator is provided with an audible sequence of discrete instructions. Thus, upon approaching an intersection, the vehicle information system provides an audible instruction as to the direction in which to turn.
Another approach to route guidance uses a displayed map on which the planned route and the vehicle's location are dynamically displayed. The operator uses the displayed map to decide when and where to turn in order to follow the planned route. These systems may be augmented with audible directions.
Some guidance systems are aided by in-vehicle sensors that are used to estimate the location of the vehicle. For instance, a magnetic compass may be used to estimate the direction of travel, and odometry may be used to estimate the distance traveled. In other systems, the location of the vehicle can be estimated using the Global Positioning System (GPS).
Additional information may be provided to vehicle information systems including traffic related information. By way of example, traffic advisories may be broadcast to specially equipped in-vehicle radio receivers. Moreover, some vehicle information systems include information as to retail locations, such as gas stations, in the vicinity of the vehicle. The recent price of gas at the particular stations may also be provided.
Other vehicle information systems have been developed that provide more comprehensive monitoring of the environment of the vehicle. By way of example, U.S. Pat. No. 6,161,071, issued Dec. 12, 2000 to Shuman et al., which is herein incorporated by reference, discloses a computing architecture for a land-based vehicle. The system disclosed therein includes various types of sensors and data inputs which are used to generate a three dimensional map of the vehicle and its environment. The generated maps can be used to issue warnings to the operator of objects in the vehicle path and to change the direction of headlamps to track a road upon which the vehicle is located.
While a substantial amount of information is available to the operator of a vehicle, the manner in which the data is presented is not optimal. By way of example, navigation system data is typically rendered on a screen which is located below the top of the vehicle dashboard. Accordingly, the operator is forced to look away from the road, increasing the potential of an accident, to observe the displayed data. Additionally, different lighting conditions between the windshield and the display screen can require some period of readjustment before the operator is able to perceive conditions viewable through the windshield. Any such delay reduces the opportunity of the operator to avoid unexpected road hazards.
An advance over the use of a display located below the dashboard for the display of information is the use of virtual displays on the windshield of the vehicle. By way of example, U.S. Pat. No. 6,791,511, issued on Sep. 14, 2004 to Eschler et al., which is herein incorporated by reference, discloses a display device which displays a virtual image on the windshield of a motor vehicle. Thus, information as to the road course in front of the vehicle may be displayed on the windshield. The operator, however, may not be able to visually correlate the virtual image to the actual road course. Additionally, the operator must change focus between the virtual image and the actual road course.
What is needed is a system which automatically guides an operator during operation of a vehicle. What is further needed is a system that can enhance the ability of the operator to easily correlate the data presented to viewable objects. A further need exists for a system which can provide data to the operator of a vehicle without the need to change the focal point of the operator.